This invention relates generally to compressor blades for gas turbine engines, and, more particularly, to a hollow composite blade structure which is durable, light in weight and of sufficient strength to render it free of flutter in operation.
Turbine engines have a variety of practical applications, the most important of which is in the field of aviation. In the propulsion of aircraft, the gas turbine power plant as a turbo prop or turbine jet engine has replaced the reciprocating engine in large, high speed aircraft. This change is due primary to its high power to weight ratio and its ability to be built in large horsepower sizes with high ratio of thrust per frontal area. In addition, turbine engines are useful in gas pipe line transmission, generating power in refineries and other industries as well as being useful in the marine transportation area and for the electric power generation.
A recent development in turbine blade construction has been the composite turbine or compressor blade. Such a composite blade, as those made from boron epoxy or boron aluminum tapes have been fabricated by building up the airfoil planform by compressing stacked layers of the tapes either with or without a core or spar. Once the planform had been established the entire unit would be set or cured in a well known manner. The problem encountered with the composite blade is that the blade is generally heavy and is highly expensive to manufacture due to the amount of material required to fabricate the same.